package cn.tedu.fb;

import cn.tedu.web.util.JsonResult;
import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * 当嗲用后台的商品调用服务失败
 * 执行网关中的这个降级类.想客户端但会降级结果
 */
@Component
public class orderFB implements FallbackProvider {
    /**
     * 设置当前降级类.针对那个后台服务降级
     * item-service: 值针对商品降级
     * *：    针对所有服务都应用降级类
     * null:  针对所有服务都应用降级类
     * @return
     */
    @Override
    public String getRoute() {
        return "order-service";
    }

    /**
     * 发回给客户端的降级响应数据
     *
     * @param route
     * @param cause
     * @return
     */
    @Override
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
        return new ClientHttpResponse() {

            @Override
            public HttpStatus getStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR;
            }

            @Override
            public int getRawStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.value();
            }

            @Override
            public String getStatusText() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.getReasonPhrase();
            }


            @Override
            public void close() {
                //用来关闭下面的输入流
                //ByteArrayInputStream 不占用底层系统资源,不需要关闭

            }

            @Override
            public InputStream getBody() throws IOException {
                //JsonResult {code:500,msg:调用服务失败,data:null}
                String json = JsonResult.build().code(500).msg("调用后台服务器失败").toString();
                return new ByteArrayInputStream(json.getBytes("UTF-8"));
            }

            @Override
            public HttpHeaders getHeaders() {
                HttpHeaders h = new HttpHeaders();
                h.add("Content-Type","application/json;charset=UTF-8");
                return h;
            }
        };
    }
}
